This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The amount of oxalate synthesized in the body is a critical factor in the primary hyperoxalurias, rare genetic diseases that can result in renal failure and premature death. Oxalate synthesis may also contribute to idiopathic calcium oxalate stone disease. The biochemical pathways that result in oxalate synthesis have not been clearly defined. Studies performed over 4 decades ago suggested that the metabolism of the amino acid, glycine, may make an important contribution to endogenous oxalate synthesis. The interpretation of these results is uncertain because of the methodology used. We wish to reinvestigate the metabolism of glycine using state-of-the-art technology. We have in our laboratory an ion chromatograph coupled to a mass spectrometer that will be used to follow the metabolism of a stable isotope of glycine to glycolate, oxalate and hippuric acid. With this sensitive instrumentation we will be able to accurately determine the amount of oxalate synthesized from glycine by normal subjects in the fasted state. This information will increase our understanding of the pathways that lead to oxalate synthesis and has the potential to lead to new strategies to limit oxalate synthesis.